Dynamo-electric machine



J. L. McK. YARDLEY,

DYNAMO ELECTRIC MACHINE. APPLICATION FILED APR.I4, 19l3- 1,392,039. Pa tenwdSep 27,1921.

2 SHEETS-SHEET 1.

1. L. McK. YARD LEY.

DYNAMO ELECTRIC MACHINE.

' APPLICATION men APR. H, 1913.

1,392,039. PatentedSept. 27; 1921.

2 SHEETS- SHEET 2.

' WITNESSES: v I I f m 3 I ALITORNEY JOHN L. YARDLEY, OFPITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WESTING- HOUSE ELECTRIC SYLVANIA.

AND MANUFACTURING COMPANY, A CQRPORATION OF PENN- DYNAMO-ELECTRI C IVIACHINE.

Specification of Letters Patent. Patented Se t. 27, 192] Application filed April 14, 1913. Serial Nb. 760,925.

To allwhom it may concern:

Be it known that I, JOHN L. McK. YARD- LnY, a citizen of theUnited States, and av resident of Pittsburgln'in the county of Allegheny and State of Pennsylvania, have-in vented a new and useful Improvement in Dynamo-Electric Machines, of which the following is a specification.

My invention relates to dynamo-electric machines and it has special reference to synchronous booster rotary converters and to means for improving the commutatingconditions thereof. p p I p The object of my invention is to provide a simple, effective and exact automatic c mQ pensating means forsecuring good commutating conditions in rotary converters under all conditions of load. i 1 k By a synchronous booster rotary converter, I mean a machine combining a rotary converter and a mechanically associated alternating current booster which have their rotor windings connected in series circuit relation. The preferable design disposes both converter and booster on a common shaft The field frames are cast integrally and the series rotor connections are permanent, there being no slip rings on the converter proper. i

The purpose .of the combination is ito boost or buck the incoming alternating current voltage for maintaining a predetermined direct current voltage on the converter. I

' The. total armature reaction of arotary converter, that is, the resultant reaction ob tained by integration around the entire armature circumference of the'reacting effects 7 of both the alternatingand direct currents present during operation in the armature coils, is normally that of a motor, or, in other words, the alternating current reaction predominates. However, if ;we take simply thecommutating zone, that.is, the: region directly beneath the commutator brushes, which. region is, of course, allthat we .are concerned with when considering commit. tating conditions, it has been shown mathematically andproved by tests that .the normal reaction in this zone is that of a generator, or, to state it differently, the direct current reaction is the greater. v

The synchronousjbooster rotary converter has diiferent electrical characteristics from the: simple rotary converter, especially as regards armature reaction. In operating the combined machine, the excitation of the field coils of the booster maybe reversed, thereby causing the generated voltage to raise or lower the voltage impressed at the collector rings. Vvhen the field is excited so that the voltage generated bucks the impressed voltage, the booster acts the field is excited so that the voltage generated boosts the impressedvoltage, the booster acts asa generator.

In the former case, the rotary converter, being partially driven by the booster, deliverssome of its direct current energy as a, generator. The, additional generative or direct current armature reaction present under the brushes by reason of this generator action of the rotary, is, therefore, additively combined with they generative reaction of the simple converter. On the otherhand, in. the latter, case, where the booster is acting as a generator, being driven by the converter acting partially as amotor, the motor action of the simple converter is correspondingly augmented, and the additional motor or alternating current reactioninthe comniuitat ng zone, being in opposition to the above-mentionedgenerative reaction of the simple converter in this zone, is, .consequently, subtracted therefrom.

I The commutating field strength of the synchronous booster rotary converter must fulfil two requirementsif it is to successfully maintain good I commutating conditions: first, the field strengthmust vary with the load current of tlie conVerter proper; and second, the fieldstrength must vary according to the additional armature reaction caused bythe booster current, which reaction may be. either positive or negative, as hereinbefore described. V

Heretofore, thefirst recited requirement has been recognized and satisfied by means ofaa series 'commutating field connected to the main line, thus having load current flowing through said field atall times. second requirement, however,'has either not been recognized or has bafiied all attempts to properly meet it. a

According to my invention, I provide automatic means for successfully fulfilling both prescribedrequirements. A series com mutatingwinding is provided for varying The I the commutating field strength in proportion to the load current, and, as an aid thereto, a commutating series winding is connected in series with a suitable rheostat across a low-resistance shunt in the main line, either directly or secondarily through a relay. For varying said field strength in proportion to the total armature reaction of the converter, the rheostat in the commutating shunt field circuit is mounted on the same shaft as the rheostat in the booster field circuit, thus varying the commutating field strength in proportion to the field strength of the booster. The additional armature reaction hereinbefore considered is proportional to the additional alternating or direct currents flowing in the rotary converter armature upon excitation of the booster, and, consequently, the reaction in question bears a readily determined relation to the field current of the booster. In addition, a main series commutating winding is provided to compensate for the demagnetizing effect of armature reaction, and an auxiliary main shunt field winding is connected in series circuit relation with the booster field winding to compensate for changes in saturation and to improve the power-factor of the machine under all conditions of load.

In the accompanying drawings, Figure 1 is a diagrammatic view of apparatus and electrical connections embodying my invention; Fig. 2 is a diagrammatic view of the field windings and connections of the rotary converter and booster shown in Fig. 1; and Fig. 8 is a view of a modification of my invention wherein apparatus that is adapted for manual operation is substituted for the automatic devices shown in Fig. 1.

Referring to the drawings, a rotary converter 1 is mechanically connected to an alternating current booster 2 by means of a common shaft 3, and the rotor windings (not shown) are electrically connected in series circuit relation. A plurality of conductors 4 serve to connect the booster 2 to an alternating current supply circuit (not shown).

A main shunt field winding 5, an auxiliary shunt field winding 6 and a main series field winding 5 are wound on mam polar projections 7 of the converter 1, and commutating series windings 8 and 9 are disposed on interpolar pro ect1ons 10. The series winding 9 is connected in series circuit relation with the armature 11 of the converter, thus being traversed by the full line direct current at all times. A main shunt field winding 12, that is disposed on main polar projections 13 of the booster 2, is connected in series with the auxiliary main field winding 6, for the purpose of maintaining a high power-factor on the converter under all conditions of load.

In Fig. 1, the main shunt field winding 5 of the converter 1 is connected across the di rect current terminals 14. The commutating series winding 9, the main series field winding 5 and a shunt 15 are connected in series circuit relation with the armature 11. The auxiliary main field winding 6 and the booster main field winding 12 are connected to a suitable reversing rheostat 16 that is connected across the direct current line 17 The series commutating winding 8 is connected to a suitable reversing. rheostat 18 which is connected to any suitable source of direct current and is associated with suitable auxiliary apparatus and circuits, to be described hereafter in detail, by means of which the potential difference across the terminals of the rheostat 18 is varied in accordance with the potential difference across the line shunt 15.

The relay 19 is of the differential type, comprising a plurality of oppositely-(lisposed, magnet coils 20 and 21, and a swinging arm 22, biased by oppositely-disposed balanced springs 23 to the open position, and mounted between them. The operation of the arm 22 is dependent upon the electromagnets 20 and 21, the former being connected across the shunt 15 in the main direct current line, and the latter being connected across an independent direct current generator 2 1, as hereinafter set forth.

Controlled by the relay 19, is an electromagnetically actuated double-pole reversing switching device 25, which embodies a plurality of solenoids 26 and 27 severally adapted to be oppositely energized tl'irough predetermined connections of the swingin across the direct current line 1'7. Main contact members 28 are thus thrown either in forward or reverse position.

A motor 29, preferably of an alternating current constant speed type, is controlled by the switching device 25. A resistor 30 is adjustably mounted on the shaft of said motor, and the direct current generator 24, preferably of the commutating pole compound type, has a shunt field winding 31 in series with the resistor 30. Another motor 82, similar to the motor 29, is employed to drive the generator 24, across the terminals of which is connected the coil 21 of the differential relay 19, as hereinbefore stated.

The commutating winding 8 of the converter 1 is connected to the reversing rheostat 18, which is also connected in series with the generator 2 1. The second reversing rheostate 16, in the booster field'winding circuit 12, is mounted on a common actuating shaft 33 with the rheostat 18. An automatically controlled motor 34 serves to drive said shaft, as hereinafter described.

Customers supply buses 35 are severally connected with the sub-station buses 17 by the usual, or any suitable, system of feeder circuits 36. The voltage of the booster 2 and, consequently, the direct current voltage delivered by the converter 1, is secondarily controlled by the voltage at a certain customers buses 37 in thefollowing manner: A voltage relay 38, comprising a magnet coil 39 which is connected across the buses 37, and a swinging arm 40 biased by a spring 41 and adapted to severally make connections in a plurality of circuits, dependent upon the strength of the electromagnetic. force exerted by said coil, and therefore primarily dependent upon the voltage at the buses 37. Controlled'by the relay 38, is an electromagnetically-actuated double-pole reversing switching device 42 similar tothe device 25 hereinbefore described. The reversing switch 42 controls the operation of the motor 34 which actuates the common shaft 33 of the reversing rheostats 16 and 18, thereby controlling the current in the booster field winding circuit 12 and the commutating series. winding circuit 8, and therefore controlling the direct current line voltage. I

.An overload relay 43, also connected in the voltage relay secondary circuit 44, comprises a solenoid 45 which is connected across the shunt 15 in the main direct current line,,and a plunger 46 which is operated by said solenoid and is adapted to make connections in the circuit 44. Normally, said plunger is in its lowest position 47 which permits of connections for throwing the switching device 42 in either direction and thereby operating the motor 34.

If the converter should become 'overloaded, one remedy resides in lowering the voltage, as is well understood. The overload relay 43 accomplishes the reduction of the voltage, under overload conditions, in a manner described below.

With an unusually heavy line current flowing the voltage drop across the shunt 15 in the main line becomes high enough to energize the solenoid 45 of the overload relay 43 sufficiently to cause said relay to raise the plunger 46 out of the normal position 47, whereby said plunger makes new contact connections 48 that are adapted to throw the switching devicein only one direction, viz: The direction which actuates the motor 34, which is controlled by the device 42, to operate the rheostats 16 and 18 to increase the resistance of the field circuits in which they are connected, thereby ultimately reducing the direct current line voltage. a

When the auxiliary machine 2 is boosting the alternating voltage impressed on the converter, the machine 2is operating as a generator deriving mechanical power from the converter and increasing the motorcreaction of the latter. The reaction of the converter in the commutating zone being normally-that of a generator, it will be decreased by the increase in motor reaction and a weaker commutating field is necessary. Under these .conditions, the commutating winding 8 opposes the main commutating winding 9.

On the other hand, when the auxiliary machine 2 is bucking the alternating voltage impressed on the converter, the machine 2 acts as a motor, driving the converter and increasing the generator reaction of the latter. The reaction is accordingly increased in the commutating zone and this effect is obtained by having the winding 8 assist the winding 9.

The necessary reversal of the direction of current flow in the winding 8 to satisfy both of the above conditions is brought about by energizing the winding 8 from the reversing rheostat 18 which is actuated by the same means as those employed to actuate the rheostatl6 and to cause the machine 2 to act either boosting or bucking.

When the machine 2 is boosting, the

iron of the converter is saturated to a The connections of the winding 6 are antomatically reversed to satisfy all of the above conditions by having it connected in series with the booster field, so that when the latter is reversed to change the action from bucking to boosting, or vice versa, the former will be changed simultaneously.

The several induction motors preferably employed in my invention are adapted for connection to a suitable alternating current supply circuit 49 through a transformer 50.

The operation of the automatic control' apparatus hereinbefore described may be stated as follows: I

The differentially wound magnet coils 20 and 21 of the differential relay 19 have impressed upon them the voltage across the shunt 15 and the voltage across the terminals of the auxiliary direct current generator24, respectively. So long as the electromagnetic forces exerted by said coils remain equal in strength, the swinging arm 22 is held by the springs 23 in its off position. However, when line load current changes by a predetermined amount, one coil becomes sufiiciently energized to overbalance the pull of the other and move the arm 22 into a circuit-completing contact position.

One of the solenoids 26 and 27 embodied in the double-pole switching device is thereby energized, the switch proper 28 is thrown in a predetermined direction, starting the motor 29 that operates the resistor 30 in the field circuit of the direct current generator 24, the voltage of which is accordingly changed, and, by reason of the special design of said generator, the voltage thereof is varied in proportion to the variations of line voltage across the shunt 15. It will be understood that, in case the voltage across said shunt increases, the mechanism is adapted to increase the direct current generator voltage, and, if the shunt voltage decreases, the generator voltage also decreases.

The above process continues until the pulls of the several magnet coils 20 and 21. are again balanced, when the swinging arm 22 of the differential relay 19 drops back to its off position, being held by the spring. 23. As the commutating shunt field circuit 8 is connected across the direct current generator 24, the current therethrough varies in proportion to the generator voltage, and, consequently in proportion to the direct current in the converter, thus fulfilling one of the two theoretically prescribed requirements for proper adjustment of the commutating field winding strength.

The ope ation of the voltage relay 38 and apparatus controlled thereby is as follows: The magnet coil 89, connected across a cer tain customers busses 37, under normal conditions, holds the swinging arm 1O in its off position against the tension of the spring 11. Upon a predetermined change in voltage, however, either the coil 39 or the spring 11 exerts the greater force temporarily, and, consequently, the swinging arm 10 assumes a circuit-completing contact position. One of the plurality of solenoids embodied in the double-pole switching device 12 is thereby energized, the switch proper is thrown in a predetermined direction, starting the motor 3 1% that drives the shaft 33, upon which are mounted the several reversing rheostats 16 and 18 connected to the communicating series winding 8 and the booster field winding 12, respectively. The resistance in said circuits is thereby simultaneously varied in proportion to the voltage delivered by the booster 2, and, consequently, the current in the commutating winding 8 is varied in like proportion, thereby fulfilling the second theoretical requirement for maintaining proper adjustment of the commutating field winding strength under all conditions of load. It will be understood that the process just described simultaneously and automatically varies the booster field current and armature voltage to maintain a predetermined direct current voltage on the rotary converter. 7

In the modification of my invention shown in Fig. 3, a manually operated wheel 51 on the shaftis substituted for the motor and related control apparatus. Also, the commutating winding 8 is connected to the rheostat '18 which is connected directly across the line shunt 15, the auxiliary direct current generator 24 and related apparatus being eliminated. The direct current line voltage is thus maintained at the proper value by hand adjustment, whereupon the commutating field strength automatically takes a value such that the best commutating conditions are obtained.

In the accompanying claims, I shall, for the sake of brevity, employ the term series field and shunt field to denote, respectively, fields in which other things remaining constant, the current varies in some definite ratio with respect to the direct load current delivered by the rotary converter, and fields in which, other things remaining constant, the current varies in some definite ratio with respect to the voltage across some portion of the direct current load circuit. .While the ratio in any specific case may be quite difficult to determine, because of the number of elements contributing to it, the said ratio is, nevertheless existent and the above assumption is a fair one.

Accordingly, the windings 5 and 9 will obviously be series windings and the winding 5 will obviously be a shunt winding. Since the windings 6 and 12 are connected indirectly across the mains 17, they must be classified aslshunt windings, and, since the current in the winding 8 varies in accordance with the current in the shunt 15, it must be classified as a series winding.

I do not wish to be restricted to the specific structures and details herein set forth, but desire that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. The combination with a plurality of dynamo-electric machines mechanically associated and electrically connected in series circuit relation, one of which is of the commutator type, of automatic means mechanically associated with both machines for regulating voltage and securing good commutating conditions on said commutating machine. v

2. The combination With a plurality of dynamo-electric machines mechanically associated and electrically connected in series circuit relation, one of which is of the commutator type, of automatic means mechanically associated with both machines for regulating the voltage and securing good commutating conditions on said commutating machine under all conditions of load.

3. The combination with a plurality of dynamo-electric machines mechanically associated and electrically connected in series controlled, load-responsive apparatus acting in conjunction with certain of said field windings of both machines for regulating the voltage and securing good commutating conditions on said commutating machine under all conditions of load.

5. The combination with a dynamo-electric machine adapted to deliver alternating and direct currents and provided with a plurality both of main field and of commutating field windings, and'a second dynamo-electric machine mechanically associated with said first machine andelectrically conf nected-in series therewith and provided with a main field winding, of automatic electrically-controlled means for simultaneously controlling the current in certain of said field windings.

6. The combination with a dynamo-electric machine adapted to deliver alternating and direct currents and providedwith a plurality both of main and of auxiliaryfield windings, and a second dynamo-electric machine mechanlcally associated with said first machine and electrically connected in series therewith and provided with a field winding, of automatic, electrically controlled, load-compensating means for simultaneously controlling the current in the field winding of said second machine and the current in one of the auxiliary field windings of said first machine.

7. The combination with a dynamo-electric machine adapted to deliver alternating and direct currents and provided with a plurality of main and auxiliary field windings of said first machine.

-8. The combination with a rotary converter, a fieldmagnet frame therefor having a plurality of main polar projections and commutating polar projections disposed intermediate thereof, the main projections being provided with a main field winding and the commutating projections being provided with commutating windings, and a booster mechanically associated with said converter and electrically connected in series therewith and provided with a field winding, of automatic, electroresponsive means dependent upon changes in lineload conditions for simultaneously controlling the current in the field winding of said booster and the auxiliary shunt field winding of said converter. r 5

. 9. The combination with a dynamo-electric machine adapted to deliver alternating and direct current and provided with a main field winding and auxiliary and commutating field windings, of a second dynamo-electric machine rigidly associated and electrically connected in series circuit relation therewith and provided with a main field winding, and automatic, load-controlled and electrically actuated apparatus for controllingthe currents in said windings in order to maintain a predetermined voltage and to secure good commutating conditions on said first machineunder all conditions of load.

10. The combination with a rotary'converter provided with a main field winding and auxiliary and commutating field windings, of an alternating currentbooster rigidly associatedand electrically connected in series therewith and provided with a main field winding, and automatic, load-controlled and electrically actuated apparatus for controlling the currents insaid windings so as to maintain apredetermined voltage'and to secure good commutating conditions on the converter under all conditions of load.

11. The combination with adynamo-el'eci tric machine adapted to deliver alternating "and direct currents and provided with a plurality both of main and of commutating field windings, and a second dynamo-electric machine mechanically associated with said first machine, and electrically connected in series therewith and provided with a field winding, of automatic," electro-magnetically actuated means dependent upon line load conditions for varying the voltage applied to one of the commutating windings of said first machine, and automatic means for simultaneously controlling the current in'certain of said field windings for maintaining a predetermined voltage and securing good commutating conditions on said first machine under all conditions of load.

'12. Thecombination with a dynamo-electric machine adapted to deliver alternating and direct currents and-provided with a plurality of main field windings and with a plurality of commutating field windings, and a second dynamo-electric machine mechanicallyassociated'with said first machine and electrically connected in series therewith and provided with a field winding, of automatic electromagnetically actuated means controlled by variation of line load conditions for varying the voltage applied to one of th commutating windings of said first machine, and automatic means for simultaneously controlling the current in the field winding of said second machine and the current in one of the shunt field wind ings of said first machine.

13. The combination with a dynamo-electric machine adapted to deliver alternating and direct currents and provided with a main field winding auxiliary series and shunt field windings, and auxiliary commutating windings, and a second dynamoelectric machine mechanically associated with said first machine and electrically con nected in series therewith and provided with a field winding, of automatic, electro-magnetically actuated means controlled by variation of line load conditions for correspondingly varying the voltage applied to an auxiliary commutating winding of said first machine, and automatic means for simultaneously controlling the current in the field winding of said second machine and the current in the auxiliary shunt field winding of said first machine.

14; The combination with a dynamo-electric machine adapted to deliver alternating and direct currents, a field magnet frame therefor having a plurality of polar projections one portion of which is provided with a main field winding and with an auxiliary field winding and another portion with an auxiliary commutating winding, and a second dynamoelectric machine mechanically associated with said first machine and electrically connected in series therewith and provided with a field winding, of automatic, electro-magnetically actuated mechanism controlled by predetermined variation of line load conditions, an independent sou-roe of electrical energy controlled by said mechanism for varying the voltage applied to the auxiliary commutating winding of said first machine proportionately to the varia tion of line load current, and automatic, electro-magnetically controlled, electrically operated means for simultaneously controlling the current in the field winding of said second machine and the current in the auxiliary shunt field winding of said first machine.

15. The combination with a rotary converter, a field magnet frame therefor having aplurality of main polar projections and intermediate commutating polar projections, the main projections being provided with a main field winding and with an auxiliary field winding and the commutating projections being provided with an auxiliary commutating winding, and a booster mechanically associated with said converter and electrically connected in series therewith and provided with a field winding, of a shunt in series with the main direct current line automatic, electro magnetically actuated mechanism selectively controlled by predetermined changes in line load conditions, an independent source of electrical energy, a controlling device therefor electrically actuated by said mechanism for varying the voltage applied to the auxiliary field winding of said converter proportionately to the changes of line load current, and automatic, electro'magnetically controlled electrically operated mechanism for simultaneously controlling the current in the field winding of said booster and the current in the auxiliary field winding of said converter.

16.. The combination with a rotary converter, a field-magnet frame therefor having a plurality of main polar projections and commutating polar projections disposed intermediate thereto, the main projections being provided with a main field winding and with an auxiliary field winding and the commutating projections being provided with auxiliary commutating windings, and a booster mechanically associated with said converter and electrically connected in series therewith and provided with a field winding, of-a low-resistance shunt in series with the main direct current line, an automatic relay electromagnetically actuated by predetermined variations in voltage drop across said shunt, an adjustable resistor, operating means therefor controlled by said relay, a motor-driven direct-current generator connected across an auxiliary commutating winding of said converter and having its own field winding connected in series-circuit relation with said resistance for varying the generator voltage applied to said auxiliary commutating winding proportionately to the variation of voltage drop across said shunt, asecond automatic relay dependent upon variation in line voltage, a switching device operated by said Second relay, and poweractuated means controlled by said device for simultaneously controlling the current in the field winding of said booster and the current in the auxiliary field winding of said converter.

17. The combination with'a rotary con verter, a field magnet frame therefor having a'plurality of main polar projections and commutating polar projections disposed intermediate thereto, the main projections being provided with a main field Winding and with an auxiliary field winding and the commutating projections being provided with auxiliary commutating windings, and

a booster mechanically associated with said.

converter and electrically connected in series therewith and provided with a field winding, of a low-resistance shunt in ser es Wi h he mai rec curr n line, an automatic differential relay electro magnetically actuated by predetermined changes in voltage drop across said shunt, an adjustable resistance, power-actuated operating means therefor controlled by said relay, an independently driven direct current generator connected across an auxiliary commutating winding of said converter, also across one element of the differential relay and having its own field winding connected in series circuit relation with said resistor for varying the voltage applied to said auxiliary commutating' winding proportionately to the changes in voltage drop across said shunt, an automatic relay 0peratively dependent upon predetermined variations inline voltage, a switching device operated by said relay and poweractuated means controlled by said device for simultaneously controlling thecurrent in the field winding circuit of said booster and the current in the auxiliary field winding of said converter.

18." The combination-with a plurality of dynamo-electric machines mechanically associated and electrically connected in series circuit relation, of automatic means electrically associated with both machines for regulating the voltage and securing good commutating conditions on one of said machines under all conditions of load, and electroresponsive means dependent upon predeter-' mined overload conditions i for controlling the line voltage. i

19. The combination with a dynamo-electric machine adapted to deliver alternating and direct currents and provided with a plurality both of main and of commutating field windings, and a second dynamo-electric machine mechanicallyassociated with said first machine and electrically connected in series therewith and provided with a field winding, of automatic, electrically-controlled means for simultaneously controlling the current in certain of said windings, and electrically operated means" dependent upon predetermined load conditions for lowering the line voltage.

20. The combination with a rotary con ve'rter providedwith a main field winding and auxiliary field and commutating windings, of an alternating current booster.

rigidlyassociated and electrically connected in series therewith and provided with a main fieldwinding, automatic load-controlled and electrically-actuated apparatus for maintaining a predetermined voltage and securing good commutating conditions on the converter, and electrically operated mechanism dependent upon a predetermined increase in line load. current for causing a decrease in the booster voltage.

21. The combination with a rotary converter, a field magnet frame therefor having a'plura'lity of main polar projections and commutating polar projections disposed intermediate thereto, the main projections being provided with a main field winding and with an auxiliary field winding and the commutating projections provided with auxiliary commutating windings, and a booster mechanically associated with said converter and electrically connected in series therewith and provided with a field winding, of'a lowresistance shunt in series with the main direct current line, an automatic differential relay electro-magnetically actuated by predetermined changes in voltage drop across said shunt, an adjustable resistance member operated by suitable means controlled by said relay, 'an' independently driven direct current generator connected across the auxiliary field winding of said converter, also across one element of the differential relay and having its own field winding connected in series circuit relation with said resistor for varying the generator voltage applied to said auxiliary field winding proportionately to the changes in voltage drop across said shunt, an automatic relay operatively dependent upon predetermined variations in line voltage, a switching device operated bysai'd relay and power-actuated means controlled by said device for simultaneously controlling the current in the field winding of said booster and the current in an auxiliary commutating winding of said converter, and an overload relay dependent upon predetermined increase in line load current for operating said switching device and power-actuated means controlled thereby to cause a decrease in the booster voltage.

22. The combination with a plurality of dynamo-electric machines mechanically ass sociatedfand electricallyconnected in series circuitrelation, one of which is of the commutator type, of means electrically associated with both machines for regulating the voltage and securing good commutating conditions on said commutating machine, and electrical means for maintaining a high power-factor on said machine, under all conditions of load. 7 j

23. The combination with a plurality of dynamo-electric machines mechanically associatedand electrically connected in seriescircuit relation, one of said machines being of the commutator type and provided with commutating field windings and both of said machines being provided With main field windings, of automatic,- electrically controlled apparatus acting in conjunction with certain of said main and commutating field windings for regulating the voltage and securing good commutatin'g conditions on said commutating machine, and connections to certain other of said field windlngs for regulating the power factor of said commuverter provided with main series and shunt field windings, an auxiliary main shunt field winding and commutating-series field windings, of an alternating current booster rigidly associated and electrically connected in series therewith and provided with a main field winding, automatic, load-controlled and electrically-actuated apparatus adapted to control the commutating field strength to maintain good commutating conditions on the converter, and a series circuit connection of the auxiliary shunt field of the converter and the booster main field for maintaining a high power-tacter on said converter under all conditions of load.

The combination with a plurality of dynamo-electric machines mechanically associated and electrically connected in series circuit relation, one of which is of the commutator type, of means mechanically associated with certain parts of both machines for regulating the voltage and securing good commutating conditions on said commutating machine.

26. The combination with a plurality of dynamo-electric machines mechanically associated and electrically connected in series circuit relation and provided with a plurality of field circuits, one of said machines being of the commutator type, of means mechanically associated with said field circuits for regulating voltage and securing good commutating conditions on said commutating machine.

27. The combination with a plurality of dynamo-electric machines mechanically associated and electrically connected in series circuit relation and severally provided with field circuits severally including adjustable resistors, one 01"? said machines being of the commutator type, of means mechanically associated with said resistors for regulating voltage and securing good. commutating conditions on said commutating machine.

28. The combination with a plurality of dynamo-electric machines mechanically associated and electrically connected in seriescircuit relation, one of said machines being of the commutator type and provided with a commutating field winding and the other of said machines being provided with a main field winding, of a plurality of resistors severally connected to the-said field windings, anda common operating device for said resistors for simultaneously regulating voltage and securing good commutating conditions on'said commutating machine.

29. The combination with a dynamo-electric machine adapted to deliver alternating and direct current and provided with a plurality both of main and of commutating field windings, and a second dynamo-electric machine mechanically associated with said first machine and electrically connected in series therewith and provided with a field winding, of means dependent upon line load conditions for varying the voltage applied to one of the commutating windings of said first machine, and means for simultaneously varying the current in certain of said field windings for vmaintaining a predetermined voltage and securing good commutating conditions on said first machine under all conditions of load.

30. The combination with a dynamo-electric machine adapted to deliver alternating and direct current and provided with a main field winding and auxiliary field and commutating windings, and a second dynamoelectric' machine mechanically associated with said first machine and electrically connested in series therewith and provided with a field winding, of electrical means dependent upon variation of line load conditions for correspondingly varying the voltage applied to an auxiliary commutating winding of said first machine, and mechanical means for simultaneously varying the current in the field winding of said second machine and the current in the auxiliary field winding of said first machine.

31. The combination with a rotary converter provided with main field windings and auxiliary field and commutating windings, and an alternating current booster mechanically associated with said rotary converter and electrically connected in series therewith and providedwith a field winding, said booster and auxiliary field and commutating windings severally including adjustable resistors, of a shunt in series with the main direct current line for varying the voltage applied to an auxiliary commutating winding of said rotary converter proportionately to the changes of line load current, and a common operating shaft for said resistors for simultaneously varying the current in the field winding of said booster and the current in an auxiliary field winding of said rotary converter.

The combination with a pluralityof dynamo-electric machines mechanically associated and electrically connected in series circuit relation, one of said machines being ofthe commutator type and provided with field and commutating windings and the other of said machines being provided with field windings, of adjustable resistors, connections from said resistors to said windings, and means mechanically associated with said resistors for operating the same in order to regulate the voltage and to secure good commutating conditions on said commutating machine.

33. The combination with a plurality of dynamo-electric machines mechanically as sociated and electrically connected in series circuit relation, one of said machines being of the commutator type and rovided with field and commutating win ings and the other of said machines being provided with field windings, of plurality of adjustable common'operating device for said resistors, and means for operating said device in order to simultaneously maintain a predeten mined voltage andsecure good commutat ing conditions on said commutating 11121- chine.

34. The combination with a dynamo-electric machine adapted to deliver alternating and direct currents and provided with a plurality both "of main and of commutating field windings, and a second dynamo-electric machine mechanically associated with said first machine and electrically'connected in series therewith and provided with a field winding, of means dependent upon line load conditions for varying the voltage applied to one of the commutating windings of said first machine, and means for simultaneously controlling the current in certain of said field windings for maintaining a predetermined voltage and securing good commutating conditions on said first machine under all conditions of load.

35. The combination with a rotary converter provided with main field windings and auxiliary main field and commutating windings, and an alternating-current booster mechanically associated with said rotary converter and electrically connected in series therewith and provided with a field winding, of a plurality of adjustable resistors, said booster and auxiliary field windings being connected to said resistors, a shunt in series with the main direct-current line for varying the voltage applied to the auxiliary commutating winding of said rotary converter proportionately to the changes of line load current, a common drive for said resistors, and means for operating said drive in order to simultaneously vary the current in the field winding of said booster and the current in the auxiliary field circuit of said rotary converter.

36. The combination of an alternatingcurrent booster, a synchronous converter associated therewith and provided with a main field winding, a series commutating field winding and an auxiliary commutating field winding, means for controlling the excitation of the booster field winding, separate means for controlling the excitation of the auxiliary commutating field winding, and means for operating the two controlling means simultaneously. 1

37. The combination of an alternatingcurrent booster, a synchronous converter associated therewith and provided with a main field winding, a series commutating field winding and an auxiliary commutating field winding, means for simultaneously varying the excitation of the booster field winding and of the auxiliary commutating field winding, and means for adjusting the rate of variation of the excitation of one of said simultaneously varied windings.

38. In combination, a rotary converter having a series commutating field winding and an auxiliary commutating field winding, a booster mechanically connected to said converter having a field winding, means for simultaneously varying and simultaneously reversing the field produced by said auxiliary commutating field winding and the field produced by the field Winding of said booster, and means dependent on the load on said converter for further varying the field produced by said auxiliary commutating field winding.

89; In combination, direct current mains,

arotary converter connected thereto having a series commutating field winding and an auxiliary commutating field winding, a booster mechanicallyconnected to said converter having a field winding, means for simultaneously varying and simultaneously reversing the voltage applied to said auxiliary commutating field winding and the voltage applied to the field winding of said booster, and means dependent on the load on said converter for varying the current in said auxiliary commutating field winding.

40. The combination with a rotary co-nverter provided with main and auxiliary cross field windings, of a booster mechanically and electrically associated therewith and provided with a field winding, currentsupply connections for all of said field windings, means for adjusting the strength and direction of the'exciting current supplied to said booster field winding which simultaneously and similarly afi'ect the current supplied to said auxiliary field winding, and means for varying the current supplied to said auxiliary field winding which do not afiect the excitation of said booster field winding. a

41. The combination with a rotary converter provided with cross field windings, of a booster electrically associated therewith and provided with field windings, means for exciting said cross field windings in accordance with the direct current of the converter, auxiliary means for adjusting both the strength and direction of the excitation of said booster field windings and for simultaneously and similarly supplying a component of excitation to said cross field windings, and independent means for varying V ditional component of commutating field which varies in direction and magnitude in accordance with the adjustments of the voltage of the booster, and in varying said last mentioned component in accordance with the load current of said converter.

43. The method of improving the commutation of a synchronous booster rotary converter of the class described, which consists in maintaining a commutating field having a component which varies both in accordance with the load current of said converter and in accordance with the booster voltage.

M. The method of improving the commutation of a commutator-type dynamo-electric machine having a variable translating device mechanically connected thereto for interchanging power in either direction therewith, which consists in producing a component of commutating field excitation which varies in direction and magnitude in accordance with said power interchange, and

in varying said component in accordance with the load current of said machine.

15. The method of improving the commutation of a commutator-type dynamo-electric machine having a variable translating device mechanically connected thereto for interchanging power in either direction therewith, which consists in producing a component of commutating field excitation which varies in accordance with the load current of said machine, and in producing another component of excitation which va ries both in accordance with said load current and in accordance with said power interchange.

In testimony whereof, I have hereunto subscribed my name this 3rd day of April,

JOHN L. MoK. YARDLEY. Witnesses:

CARY, CARTY, B. B. Hmns. 

